Inflatable devices for separating layers of tissue, and methods of using

ABSTRACT

An apparatus and method for separating a first layer of tissue from a second layer of tissue. An inflatable balloon is mounted to a delivery device. The inflatable balloon has a first, inwardly-displaced portion which everts when the balloon is inflated. The balloon is inserted into a patient between the first and second tissue layers when the balloon is in the deflated state. The balloon is then inflated so that the first portion is everted thereby minimizing trauma to the tissue layers.

This application is a continuation of Ser. No. 08/319,552, filed Oct. 7,1994, now abandoned, which is a continuation in part of Ser. No.08/287,287, filed Jul. 29, 1994 of inventors Frederic H. Moll, JeffSmith, John P. Lunsford and Albert K. Chin, now U.S. Pat. No. 5,704,372,which is a Continuation-in-Part of application Ser. No. 07/911,714,filed Jul. 10, 1992, of inventors Albert K. Chin and John P. Lunsford,now pending, which is a Continuation-in-Part of application Ser. No.07/794,590, filed Nov. 19, 1991, now issued as U.S. Pat. No. 5,309,896,of inventors Frederic H. Moll, Charles Gresl, Jr., Albert K. Chin, andPhilip K. Hopper, which is a Continuation-in-Part of application Ser.No. 07/706,781, filed May 29, 1991, now abandoned, of inventors FredericH. Moll, Albert K. Chin, Diane E. Caramore, and Frank T. Watkins III.

BACKGROUND OF THE INVENTION

The present invention relates to the field of inflatable tissueseparation devices and methods of using such devices. The apparatus andmethods of the present invention may be used in any procedure requiringdissection and/or retraction of tissue planes throughout the bodyincluding inguinal hernia repair, pelvic lymphadenectomy and bladderneck suspension in the preperitoneal space; renal, adrenal, aortic andanterior spinal access in the retroperitoneal space; penile prostheticreservoir placement in the anterior abdominal wall; and augmentationmammaplasty prosthetic placement. By way of example only, use of suchdevices and methods for hernia repair will be described.

A hernia is the protrusion of part of a body part or structure through adefect in the wall of a surrounding structure. Most commonly, a herniais the protrusion of part of abdominal contents, including bowel,through a tear or weakness in the abdominal wall, or through theinguinal canal into the scrotum.

An abdominal hernia is repaired by suturing or stapling a mesh patchover the site of the tear or weakness. The mesh patch has a roughsurface that can irritate the bowel and cause adhesions. It is thereforepreferred to install the patch properitoneally. It is intended that theterms properitoneal and preperitoneal be synonymous. The mesh patch ispreferably attached to the properitoneal fascia of the abdominal wall,and covered by the peritoneum. To attach the mesh patch to theproperitoneal fascia, the peritoneum must be dissected from theproperitoneal fascia. This is a difficult process which involves therisk of puncturing the peritoneum. Moreover, strands of properitonealfat interconnecting the peritoneum and the properitoneal fascia make itdifficult to see the site of the hernia.

The use of laparoscopic techniques to perform hernia repair is becomingincreasingly common. In the conventional procedure for carrying out ahernia repair laparoscopically, an endoscope and instruments areintroduced into the belly through one or more incisions in the abdominalwall, and are advanced through the belly to the site of the hernia.Then, working from inside the belly, a long incision is made in theperitoneum covering the site of the hernia. Part of the peritoneum isdissected from the properitoneal fat layer to provide access to the fatlayer. This is conventionally done by blunt dissection, such as bysweeping a rigid probe under the peritoneum. In this procedure, it isdifficult to dissect the peritoneum cleanly since patchy layers ofproperitoneal fat tend to adhere to the peritoneum.

In an alternative known laparoscopic hernia repair procedure, the bellyis insufflated. An incision is made in the abdominal wall close to thesite of the hernia. The incision is made through the abdominal wall asfar as the properitoneal fat layer. The peritoneum is then bluntdissected from the properitoneal fat layer by passing a finger or arigid probe through the incision and sweeping the finger or rigid probeunder the peritoneum. After the peritoneum is dissected from theproperitoneal fat layer, the space between the peritoneum and theproperitoneal fat layer is insufflated to provide a working space inwhich to apply the mesh patch to the properitoneal fascia.

During the blunt dissection process, it is easy to puncture through theperitoneum, which is quite thin. Additionally, after initial dissectionof the properitoneal space, known surgical procedures requireintroduction of various instruments in the space to conduct the surgery.These instruments can cause inadvertent puncture of the peritoneum wallafter the initial dissection. A puncture destroys the ability of thespace between the peritoneum and the fascia to hold gas insufflation;pressurized gas can travel through a puncture in the peritoneum to allowthe fluid to migrate to the abdominal cavity and degrade the pressuredifferential maintaining the properitoneal cavity. Also, it is difficultto dissect the peritoneum cleanly since patchy layers of properitonealfat tend to adhere to the peritoneum. Clearing difficult adhesions cansometimes result in a breach of the peritoneum itself.

U.S. Pat. No. 5,309,896, of which this application is aContinuation-in-Part, discloses a laparoscopic hernia repair techniquethat enables a mesh patch to be attached to the properitoneal fasciawithout breaching the peritoneum. An incision is made through theabdominal wall as far as the properitoneal fat layer. A multi-chamberedinflatable retraction device is pushed through the incision into contactwith the peritoneum, and is used to separate the peritoneum from theunderlying layers. The main end chamber of the inflatable retractiondevice is then inflated to elongate the inflatable retraction devicetowards the site of the hernia. As it inflates, the inflatableretraction device gently separates the peritoneum from the underlyinglayers. Once the main chamber of the inflatable retraction device isfully inflated, a second inflatable chamber is inflated. The secondinflatable chamber enables the inflatable retraction device to continueto separate the peritoneum from the underlying layers after the maininflatable chamber has been deflated.

One or more apertures are then cut in the envelope of the maininflatable chamber to provide access to the site of the hernia forinstruments passed into the main chamber. With such an arrangement,instruments pass through the main chamber situated between theperitoneum and the underlying layers. In this way, a patch can beattached to the properitoneal fascia without breaching the peritoneum.

Another device for separating tissue layers is disclosed in U.S. patentapplication Ser. No. 07/911,714, of which this application is acontinuation-in-part. The apparatus includes a main envelope thatdefines a main inflatable chamber. The apparatus also includes anintroducing device for introducing the main envelope in a collapsedstate between the first layer of tissue and the second layer of tissue.The introducing device inflates the main envelope into an expanded stateto separate the first layer of tissue from the second layer of tissue,and to create a working space between the first layer of tissue and thesecond layer of tissue. Finally, the apparatus includes an insufflatingdevice for introducing insufflation gas into the working space betweenthe first layer of tissue and the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofseparating a first layer of tissue from a second layer of tissue, a mainenvelope and insufflation gas are provided. The main envelope defines amain inflatable chamber. The main envelope is introduced in a collapsedstate between the first layer of tissue and the second layer of tissue.The main envelope is inflated into an expanded state to separate thefirst layer of tissue from the second layer of tissue, and to create aworking space between the first layer of tissue and the second layer oftissue. Finally, insufflation gas is introduced into the working spacebetween the first layer of tissue and the second layer of tissue.

In a first practical embodiment of an apparatus according to U.S. patentapplication Ser. No. 07/911,714, the main envelope and the introducingdevice constitute a first component that separates the first layer oftissue from the second layer of tissue to create the working space. Theinsufflation device constitutes a second component, which insufflatesthe working space to maintain the separation of the first layer oftissue from the second. The insufflation device is tubular, has ananchor flange slidably mounted on it, and has a toroidal inflatablechamber at its distal end. The anchor flange and toroidal inflatablechamber together form a gas-tight seal with the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the two-component apparatus, the introducing device is used topush the main envelope in a collapsed state through an incision throughthe second layer of tissue to place the main envelope between the firstlayer of tissue and the second layer of tissue. The main envelope isthen inflated to gently separate the first layer of tissue from thesecond layer of tissue, and to create a working space between the twolayers of tissue. An endoscope may be passed through the bore of theintroducing device into the main chamber to observe the extent ofseparation of the layers of tissue. The main envelope is then returnedto a collapsed state, and the main envelope and the introducing deviceare removed from the incision.

The insufflating device is inserted into the incision so that its distalend projects into the working space between the two layers of tissue.The toroidal inflatable chamber is inflated into an expanded state. Theanchor flange is slid distally along the insufflating device to compressthe second layer of tissue between it and the expanded toroidalinflatable chamber, and thus to form a gas-tight seal. Insufflating gasis then passed through the insufflating device into the working space tomaintain the separation of the first layer of tissue from the second. Anendoscope may be passed through the bore of the insufflating device intothe working space to observe within the working space.

In a first embodiment of a one-component apparatus according to U.S.patent application Ser. No. 07/911,714, the introducing device is alsoused for returning the main envelope to a collapsed state. A singleelongated tube provides the introducing device and the insufflatingdevice. The main envelope is detachable from the single elongated tube.The single elongated tube has an anchor flange slidably mounted on it,and has a toroidal inflatable chamber at its distal end. The anchorflange and toroidal inflatable chamber together form a gas-tight sealwith the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the first embodiment of a one-component apparatus to separate afirst layer of tissue from a second layer of tissue, the elongated tubeis used to push the main envelope in a collapsed state through anincision through the second layer of tissue to place the main envelopebetween the first layer of tissue and the second layer of tissue. Themain envelope is then inflated to gently separate the first layer oftissue from the second layer of tissue, and to create a working spacebetween the two layers of tissue. An endoscope may be passed through thebore of the single elongated tube into the main chamber to observe theextent of separation of the layers of tissue. The main envelope is thenreturned to a collapsed state, detached from the elongated tube, andremoved from the working space between the layers of tissue through thebore of the elongated tube.

The toroidal inflatable chamber at the distal end of the elongated tubeis then inflated into an expanded state. The anchor flange is sliddistally along the elongated tube to compress the second layer of tissuebetween it and the expanded toroidal inflatable chamber to form agas-tight seal. Insufflating gas is passed through the elongated tubeinto the working space to maintain the separation of the first andsecond tissue layers. An endoscope may be passed through the bore of thesingle elongated tube into the working space to observe within theworking space.

In a second embodiment of a one-component apparatus according to U.S.patent application Ser. No. 07/911,714, the introducing device is anouter elongated tube, and the insufflating device is an inner elongatedtube mounted in the bore of the outer elongated tube. The proximal endsof the tubes are flexibly coupled together. The main envelope is acylindrical piece of elastomeric material. One end of the main envelopeis everted with respect to the other, and is attached to the distal endof the outer elongated tube. The other end of the main envelope isattached to the distal end of the inner elongated tube. The maininflatable chamber defined by the main envelope is thus substantiallytoroidal. The outer elongated tube has an anchor flange slidably mountedon it. The anchor flange and the main inflatable chamber together form agas-tight seal with the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the second embodiment of a one-component apparatus to separate afirst layer of tissue from a second layer of tissue, the outer elongatedtube is used to push the main envelope in a collapsed state through anincision through the second layer of tissue to place the main envelopebetween the first layer of tissue and the second layer of tissue. Themain envelope is then inflated to gently separate the first layer oftissue from the second layer of tissue, and to create working a spacebetween the layers of tissue. An endoscope may be passed through theouter elongated tube into the main chamber to observe the extent ofseparation of the layers of tissue.

The anchor flange is slid distally along the introducing device tube tocompress the second layer of tissue between it and the main inflatablechamber, to form a gas-tight seal. Insufflating gas is then passedthrough the bore of the inner elongated tube and the bore of the mainenvelope into the working space to maintain the separation of the firstlayer of tissue from the second. An endoscope may be passed through thebore of the inner elongated tube and the bore of the main envelope intothe working space to observe within the working space.

In a further method according to U.S. patent application Ser. No.07/911,714, access through the abdominal wall to repair a hernia isprovided. The abdominal wall includes the peritoneum and an underlyinglayer. A main envelope and an insufflation gas are provided. The mainenvelope defines a main inflatable chamber. The main envelope isintroduced in a collapsed state between the peritoneum and theunderlying layer. The main envelope is inflated into an expanded stateto separate the peritoneum from the underlying layer, and to create aworking space between the peritoneum and the underlying layer.Insufflation gas is introduced into the working space, and the hernia isrepaired using an instrument passed into the working space.

In a final method according to U.S. patent application Ser. No.07/911,714, access is provided through the abdominal wall from near theumbilicus to repair a hernia. The abdominal wall includes the peritoneumand an underlying layer. A main envelope and insufflation gas areprovided. The main envelope defines a main inflatable chamber. Anincision is made at the umbilicus through the abdominal wall, includingthe underlying layer, excluding the peritoneum. The main envelope isintroduced in a collapsed state into the incision to bring the mainenvelope into contact with the peritoneum. The main envelope is inflatedinto an expanded state to separate a portion of the peritoneum from theunderlying layer, and to create a space between the portion of theperitoneum and the underlying layer. The main envelope is returned to acollapsed state. The main envelope is advanced in the direction of thehernia to the boundary of the separated portion of the peritoneum. Themain envelope is re-inflated into an expanded state to separate anadditional portion of the peritoneum from the underlying layer, and toenlarge the space. Finally, insufflation gas is introduced into at leastpart of the space.

In a variation, the collapsing, advancing, and re-inflating steps arerepeated with the main envelope being expanded to a partially expandedstate to create a narrow tunnel between the incision at the umbilicusand the hernia. At the hernia, the main inflatable chamber is inflatedinto a fully expanded state to create a working space that is laterinsufflated.

Before being inserted into a patient, the inflatable envelopes andchambers are deflated and packed into a sheath. A known method ofpacking the chamber in the deflated, compact state is to roll thechamber inwardly from opposing lateral sides as shown in FIG. 18.

A problem which occurs during inflation of the balloon packed in theknown manner of FIG. 18 is that unrolling of the balloon producesrelatively high differential motion between the balloon and tissue whichcan cause trauma to the tissue. Referring to FIG. 19, a balloon packedin the known manner of FIG. 18 is in a partially inflated state duringdeployment. During inflation, the balloon unrolls and displacesoutwardly. The top side of the balloon rubs against the upper tissuelayer and can cause trauma to the tissue layer.

SUMMARY OF THE INVENTION

The present invention solves the problems associated with known methodsof packing a deflated balloon by providing the balloon with an inwardlydisplaced portion which everts during inflation of the balloon. Theeverting portion minimizes differential motion between the balloon andthe adjacent tissue layers thereby minimizing tissue trauma.

An inflatable balloon is mounted to a delivery and inflation device. Theballoon is movable between a deflated state and an inflated state. Afirst portion of the balloon is displaced-inwardly when the balloon ispacked in the sheath so that the first portion everts when the balloonis inflated. The first portion is preferably formed as a roll which ispositioned between opposing sides of the interior surface when theballoon is in the deflated state. The balloon also preferably includes asecond portion which is also displaced-inwardly and formed in a roll.The rolls are then packed within a sheath for insertion into a patient.

The inwardly-displaced portions are rolled-up within the interior of theballoon with a rolling device having a pair spaced apart rods. The rodis introduced through the bore of the delivery device and theinwardly-displaced portion is positioned between the rods. The device isthen rotated to form the roll within the interior of the balloon.

In another preferred method of packing a balloon, the first portion isdisplaced-inwardly to separate the balloon into an upper part and alower part. The first portion and the upper and lower parts are thenrolled-up in the conventional manner and packed into a sheath. In yetanother preferred method of packing a balloon the balloon is configuredwith accordion-folds.

Other features and advantages of the invention will appear from thefollowing description in which the preferred embodiment has been setforth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the abdominal wall showing theperitoneum, the properitoneal fat layer, the properitoneal fascia, andother tissue layers.

FIGS. 2A through 2E show a two-component apparatus according to theinvention, wherein:

FIG. 2A shows the separation component of the two-component apparatusaccording to the invention.

FIG. 2B shows part of the distal part of the separation component of thetwo-component apparatus according to the invention with the mainenvelope in its everted position.

FIG. 2C shows part of the distal part of the separation component of thetwo-component apparatus according to the invention with the mainenvelope in its inverted position.

FIG. 2D shows the insufflation component of the two-component apparatusaccording to the invention with the toroidal inflatable chamber in itscollapsed state.

FIG. 2E shows the insufflation component of the two-component apparatusaccording to the invention with the toroidal inflatable chamber in itsexpanded state.

FIGS. 3A through 3I are longitudinal cross sections of the abdomenillustrating the method according to the invention of using atwo-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 3A shows an incision made through the abdominal wall, including theproperitoneal fat layer, excluding the peritoneum.

FIG. 3B shows the distal part of the separation component of atwo-component apparatus according to the invention inserted into theincision. The separation component includes the main envelope in itscollapsed state.

FIG. 3C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 3D shows the main envelope returned to its collapsed state.

FIG. 3E shows the separation component removed from the incision.

FIG. 3F shows the distal part of the insufflation component of thetwo-component apparatus according to the invention inserted into theincision.

FIG. 3G shows the toroidal inflatable chamber of the insufflationcomponent inflated to its expanded state and the anchor flange slid intocontact with the skin of the abdominal wall to provide a gas-tight seal.

FIG. 3H shows the working space between the peritoneum and theunderlying layer insufflated with a gas passed through the bore of theinsufflation component.

FIG. 3I shows additional instruments passed through gas-tight trocarsheaths into the insufflated working space to repair the hernia byattaching a mesh patch to the properitoneal fascia.

FIGS. 4A through 4C show the main embodiment of the first one-componentapparatus according to the invention, wherein:

FIG. 4A shows the main embodiment of the first one-component apparatusaccording to the invention with the main envelope in its expanded state.

FIG. 4B shows details of the area marked “A” at the distal end of thetube assembly in FIG. 4A.

FIG. 4C shows the distal part of the tube assembly with the toroidalinflatable chamber in its expanded state.

FIGS. 5A through 5D show the alternative embodiment of the firstone-component apparatus according to the invention, wherein:

FIG. 5A shows the alternative embodiment of the first one-componentapparatus according to the invention with the main envelope in itsexpanded state.

FIG. 5B shows the elongated main envelope of the alternative embodimentof the first one-component apparatus according to the invention.

FIG. 5C shows the distal part of the tube assembly of the alternativeembodiment of the first one-component apparatus according to theinvention with the main envelope in its everted state.

FIG. 5D shows the distal part of the tube assembly of the alternativeembodiment of the first one-component apparatus according to theinvention with the main envelope in its inverted state.

FIGS. 6A through 6H are longitudinal cross sections of the abdomenillustrating the method according to the invention of using a firstone-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 6A shows an incision made through the abdominal wall, including theunderlying layer, excluding the peritoneum.

FIG. 6B shows the distal part of the tube assembly of a one-componentapparatus according to the invention inserted into the incision. Thetube assembly includes the main envelope in its collapsed state.

FIG. 6C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 6D shows the main envelope returned to its fully collapsed state.

FIG. 6E shows the apparatus advanced into the incision such that theenvelope of the toroidal inflatable chamber clears the incision.

FIG. 6F shows the toroidal inflatable chamber inflated to its expandedstate.

FIG. 6G shows the anchor flange slid into contact with the skin of theabdominal wall. The anchor flange together with the expanded toroidalinflatable chamber provides a gas-tight seal.

FIG. 6H shows the space between the peritoneum and the underlying layerinsufflated with a gas passed through the bore of the apparatus.

FIGS. 7A and 7B show a second embodiment of a one-component apparatusaccording to the invention, wherein:

FIG. 7A shows the second one-component apparatus according to theinvention with the main envelope in its expanded state.

FIG. 7B shows the second one-component apparatus according to theinvention with the main envelope in its collapsed state.

FIG. 8A shows the second one-component apparatus according to theinvention with the main envelope in its expanded state and an endoscopepassed through the bore of the outer tube into the main inflatablechamber.

FIG. 8B shows the second one-component apparatus according to theinvention with the main inflatable chamber in its partially expandedstate and an endoscope passed through the bore of the inner tube andthrough the bore of the main envelope.

FIGS. 9A through 9F are longitudinal cross sections of the abdomenillustrating the method according to the invention of using a secondone-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 9A shows an incision made through the abdominal wall, including theunderlying layer, excluding the peritoneum.

FIG. 9B shows the distal part of the tube assembly of a one-componentapparatus according to the invention inserted into the incision. Thetube assembly includes the main envelope in its collapsed state.

FIG. 9C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 9D shows the main envelope returned to its partially-collapsedstate.

FIG. 9E shows the anchor flange slid into contact with the skin of theabdominal wall. The anchor flange and the partially-collapsed maininflatable chamber together provide a gas-tight seal.

FIG. 9F shows the space between the peritoneum and the underlying layerinsufflated with a gas passed through the bore of the inner tube of theapparatus.

FIGS. 10A through 10I illustrate the alternative method according to theinvention of using any of the apparatus according to the invention toseparate the peritoneum from the underlying layer near the groin, withthe apparatus inserted through an incision near the umbilicus. FIGS. 10Athrough 10H are longitudinal cross sections of the abdomen, wherein:

FIG. 10A shows an incision made through the abdominal wall, includingthe underlying layer, excluding the peritoneum.

FIG. 10B shows the distal part of the apparatus according to theinvention inserted into the incision. The tube assembly includes themain envelope in its collapsed state.

FIG. 10C shows the main envelope inflated to a partially-expanded stateto separate part of the peritoneum from the underlying layer.

FIG. 10D shows the main envelope returned to its collapsed state.

FIG. 10E shows the apparatus advanced in the direction of the groin tobring the main envelope to the limit of the separated part of theperitoneum.

FIG. 10F shows the main envelope re-inflated to a partially-expandedstate to separate an additional part of the peritoneum from theunderlying layer.

FIG. 10G shows the main envelope advanced to close to the site of thehernia and re-inflated to its fully inflated state to create a workingspace.

FIG. 10H shows the introducer component advanced through the tunnel intothe working space, and the toroidal inflatable chamber inflated to forma gas-tight seal with the entrance of the tunnel.

FIG. 10I is a plan view of the abdomen showing the insufflator componentin position with its distal end in the working space and its toroidalinflatable chamber forming a gas-tight seal with the entrance of thetunnel. The figure also shows the lesser extent to which the peritoneumis detached in the tunnel compared with in the working space.

FIGS. 11A through 11C show a retraction device having a first inflatablechamber for maintaining separation between two tissue layers, wherein:

FIG. 11A shows the first inflatable chamber in a collapsed state andcontained within a perforated sheath.

FIG. 11B and 11C show the first inflatable chamber in an expanded state.

FIGS. 12A and 12B show a second inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 12A is an end view of the second inflatable chamber for maintainingseparation between two tissue layers.

FIG. 12B is a side view of the second inflatable chamber in the expandedstate.

FIGS. 13A through 13C show the construction of the first inflatablechamber, wherein.

FIG. 13A shows the orientation of the first and second sheets, bafflesand release agent before RF welding the baffles and sheets.

FIG. 13B shows an exploded cross-sectional view of FIG. 13A with the RFwelding electrodes in position.

FIG. 13C shows the baffles attached to the first and second sheets.

FIGS. 14A and 14B show a third inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 14A is an end view of the third inflatable chamber.

FIG. 14B is a side view of the third inflatable chamber.

FIGS. 15A and 15B show a fourth inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 15A is an end view of the fourth inflatable chamber.

FIG. 15B is a side view of the fourth inflatable chamber.

FIGS. 16A and 16B show a fifth inflatable chamber for maintainingseparation between tissue layers, wherein:

FIG. 16A is an end view of the fifth inflatable chamber.

FIG. 16B is a side view of the fifth inflatable chamber.

FIGS. 17A and 17B show a retraction device having the fourth inflatablechamber advanced through a tunnel into a working space and an additionalinstrument passing adjacent the fourth inflatable chamber.

FIG. 18 shows a balloon rolled in the known manner with two rolls formedby rolling the balloon inward from opposing outer edges;

FIG. 19 shows deployment of the balloon of FIG. 18 with the top of therolls rubbing against the upper tissue layer;

FIG. 20 shows an isometric view of an inflatable balloon;

FIG. 21 shows a plan view of the inflatable balloon of FIG. 20;

FIG. 22 shows a first portion of the balloon of FIG. 20 displacedinwardly;

FIG. 23 shows a rolling device grasping an end of the first,inwardly-displaced portion between two rods;

FIG. 24 shows the rolling device of FIG. 23 used for rolling-up thefirst inwardly-displaced portion of the balloon;

FIG. 25 shows the rolling device during rolling of the first portion ofthe balloon;

FIG. 26 shows a cross-sectional view of the balloon of FIG. 20 withfirst and second inwardly-displaced portions rolled-up into first andsecond rolls and an obturator positioned therebetween;

FIG. 27 shows the balloon of FIG. 26 during inflation and deploymentbetween tissue layers;

FIGS. 28 and 29 show a cross-sectional view of a balloon packed inaccordance with another preferred method of packing a deflated balloon;

FIGS. 30 and 31 show a cross-sectional view of a balloon packed inaccordance with another preferred method of packing a deflated balloon.

FIG. 32 shows a balloon having accordion-folds; and

FIG. 33 shows the balloon of FIG. 32 in a compact state.

DETAILED DESCRIPTION OF THE INVENTION

A cross-sectional view of the abdominal wall is shown in FIG. 1. Theabdominal wall includes the several layers of tissue shown. Theperitoneum P is the innermost layer. Underlying the peritoneum areseveral layers of tissue, including the properitoneal fat layer FL andthe properitoneal fascia F. The properitoneal fascia is the layer towhich the mesh patch is preferably attached in hernia repair. Theproperitoneal fat layer separates the peritoneum from the properitonealfascia. The properitoneal fat layer is relatively weak, which enablesthe peritoneum to be separated relatively easily from the fascia.

When the peritoneum is separated from the fascia, separation takes placeat or in the properitoneal fat layer. The properitoneal fat layer canremain attached to the properitoneal fascia, or can come away with theperitoneum. Alternatively, part of the properitoneal fat layer canremain attached to the peritoneum and part of the fat layer can comeaway attached to the peritoneum. Because of the uncertainty in the pointof separation, the layer which is detached will be called theperitoneum, and the layer from which the peritoneum is detached will becalled the underlying layer. Additional layers of tissue lie between theproperitoneal fascia and the skin S.

An inguinal hernia occurs when the contents of the abdominal cavitybreak through the abdominal wall. As described above, a hernia isrepaired by attaching a piece of mesh to the abdominal wall. To preventthe mesh from causing trauma to the bowel, either through irritation ofthe bowel by the rough surface of the mesh, or by adhesion of the bowelto the mesh, it is preferred to attach the mesh to the properitonealfascia. With the mesh attached to the fascia, the peritoneum covers themesh and isolates the bowel from the mesh.

Conventional techniques of attaching the mesh patch to the properitonealfascia, both laparoscopic and normal, involve blunt dissecting theperitoneum away from the properitoneal fascia, working from inside oroutside the belly. The apparatus and methods according to the inventionenable the peritoneum to be separated from the properitoneal fascia andthe mesh patch attached to the fascia without entering the belly.

Although the following description will describe the apparatus andmethods according to the invention with respect to hernia repair, theapparatus and methods are not restricted to hernia repair. The apparatusand methods can equally well be used in other procedures in which onelayer of tissue is separated from another to form a working spacebetween the layers. These procedures include thoracoscopy in patientswith pleural adhesions; pericardioscopy, or the introduction of anendoscope into the pericardial cavity, in patients with pericardialadhesions; retroperitoneal lymph node dissection, in which theperitoneum on the distal aspect of the abdominal cavity is separatedfrom the underlying tissue which includes lymph nodes; and in separatinga blood vessel from surrounding connective tissue in the course of, forexample, a femoropopliteal arterial bypass graft procedure.

1. Two-Component Apparatus and Method of Using

The two-component form of the apparatus according to the invention isshown in FIGS. 2A through 2C. FIG. 2A shows a partially cut-away view ofthe separation component 1 of the apparatus. In the separationcomponent, the introducer tube 3 is a rigid tube having a bore with acircular cross section that can accommodate an endoscope.

The proximal end of the introducer tube is fitted with a port 5, in theproximal end 7 of which is mounted a flapper valve 2. The shutter 6 ofthe flapper valve is operated by the button 9. The seat 4 of the flappervalve additionally forms a gas-tight seal with an endoscope or otherinstrument inserted though the flapper valve into the bore of theintroducer tube 3. The port 5 is also fitted with a valve 11 to which asupply of a suitable inflation fluid can be connected.

The main envelope 12 defines a main inflatable chamber 13. The mainenvelope is fitted to the distal end 15 of the introducer tube 3. Themain envelope and main inflatable chamber are shown in their collapsedstates. The dotted line 12X indicates the extent of the main envelopewhen the main inflatable chamber 13 in its expanded state. It should benoted that although the main envelope 12 is illustrated as generallyspherical, it can be formed as oblong, “hockey puck” or disc shaped,kidney bean shaped or other shapes as are suited for the particulardissection contemplated.

The main envelope 12 is preferably formed from an elastomeric material,such as latex, silicone rubber, or polyurethane. The main envelope canalso be formed-from a thin, inelastic material such as Mylar®,polyethylene, nylon, etc. If an inelastic material is used, it should besuitably packaged to fit inside the bore of the introducer tube 3 whenin its collapsed state.

The preferred elastomeric main envelope 12 can be simply attached to thedistal end 15 of the introducer tube 3 by stretching the main envelopeover the distal end of the introducer tube, as shown in FIG. 2B. Themain envelope is then kept in place by friction resulting from thetension caused by stretching. A suitable adhesive, such as an epoxy orcyanoacrylate adhesive, may additionally or alternatively be used. Othermeans of attaching the main envelope to the inside or the outside of theintroducer tube can be used.

After attachment, the main envelope 12 is inverted into the bore of theintroducer tube, as shown in FIG. 2C. Inverting the main envelope intothe bore of the introducer tube makes it easier to use the introducertube to pass the main envelope through an incision and place it adjacentto the peritoneum as will be described next.

The first part of a method according to the invention of using theseparation component 1 of a two-component apparatus according to theinvention to separate a first layer of tissue from a second layer oftissue will next be described. As an illustration, separating theperitoneum from the properitoneal fascia in the course of repairing ahernia will be described.

FIGS. 3A through 3H show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm. long is made in the abdominal wallAW, and is carried through the abdominal wall as far as, and including,the properitoneal fat layer FL. The distal end 15 of the introducer tube3 of the separation component 1 is then inserted into the incision tobring the distal end into contact with the peritoneum P. Additionalgentle pressure detaches the part of the peritoneum in the immediatevicinity of the incision from the underlying layer, as shown in FIG. 3B.FIG. 3B shows the peritoneum detached from the properitoneal fat layerFL. The main envelope cannot be seen in these figures because it isinverted within the bore of the introducer tube 3.

A source of a suitable inflation fluid (not shown) is connected to thevalve 11. A gas, preferably air, is the preferred inflation fluid, butother gases, such as carbon dioxide, can be used. A liquid, such assaline solution, can be used, but liquids are less preferable to gasesbecause they change the optical properties of any endoscope insertedinto the main inflatable chamber 13. The flow of inflation fluid isturned on, which ejects the main envelope 12 of the main inflatablechamber 13 from the bore of the introducer tube 3.

The inflation fluid progressively expands the main envelope 12, andhence the main inflatable chamber 13 defined by the main envelope, intoan expanded state. The main envelope expands between the peritoneum andthe properitoneal fascia, and gently and progressively detaches anincreasing area of the peritoneum from the underlying layer as itexpands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4″-6″ (100-150 mm) in diameter.

Early in the process of expanding the main envelope 12, an endoscope Eis inserted into the flapper valve 2 in the port 5, as shown in FIG. 3C.The endoscope E is passed through the bore of the introducer tube 3 intothe main inflatable chamber 13. Once partially expanded, the mainenvelope 12 is sufficiently transparent for the extent of the detachmentof the peritoneum to be observed through the endoscope.

When a sufficient area of the peritoneum has been detached, the supplyof inflation fluid is turned off. The inflation fluid is then ventedfrom the main inflatable chamber, and the main envelope 12 progressivelyreturns to its collapsed state. The peritoneum remains detached from theproperitoneal fascia, however, as shown in FIG. 3D. The separationcomponent 1, including the collapsed main envelope, is then withdrawnfrom the incision I (FIG. 3E).

The insufflation component 21 of the two-component apparatus, shown inFIG. 2D, will next be described. The insufflation component 21 comprisesan inner tube 35 and an outer tube 37 mounted coaxially, with the outertube covering the inner tube over most of the length of the inner tube.The inner tube is similar to the introducer tube 3 (FIG. 2A), and is arigid tube having a bore with a circular cross section that canaccommodate a 10 mm endoscope.

The proximal end of the inner tube 35 is fitted with a port 25, theproximal end 27 of which has a flapper valve 32. The shutter 36 of theflapper valve is operated by the button 29. Additionally, the seat 34 ofthe flapper valve forms a gas-tight seal with an endoscope (not shown)or an obturator, such as the obturator 33, inserted though the flappervalve into the bore of the inner tube 35. The port 25 is also fittedwith a first valve 31 to which a supply of a suitable insufflation fluidcan be connected.

The distal end 41 of the outer tube 37 stops short of the distal end 39of the inner tube 35. The insufflation component 21 includes a toroidalinflatable chamber 43. The envelope 45 of the toroidal inflatablechamber is a cylindrical piece of a thin elastomeric material, such aslatex, silicone rubber, or polyurethane. The envelope 45 is placed overthe distal ends of the inner tube and the outer tube. The proximal end47 of the envelope is attached to the distal end 41 of the outer tube,and the distal end 49 of the envelope is attached to the distal end 39of the inner tube 35.

The bore of the outer tube 37 is spaced from the outer surface of theinner tube 35. The annular space 51 between the inner tube and the outertube inter connects the toroidal inflatable chamber 43 and a secondvalve 53. The second valve 53 is connected to a source of a suitableinflation fluid (not shown). Thus, the toroidal inflatable chamber 45can be inflated using an inflation fluid passing into the toroidalinflatable chamber via the second valve 53 and the annular space 51. Thetoroidal inflatable chamber is shown in its collapsed state in FIG. 2D,and in its expanded state in FIG. 2E.

The anchor flange 55 is slidably mounted on the outer tube 37, and canbe locked in a desired position along the length of the outer tube witha simple over-center action locking lever (not shown). As will bedescribed in detail below, the anchor flange and the toroidal inflatablechamber, in its expanded condition, enable the insufflator component 21to form a gas-tight seal to prevent insufflation gas passed through theinsufflator component from escaping.

The use of the insufflation component 21 in the second part of themethod according to the invention of using the two-component apparatusaccording to the invention will next be described. It is preferred touse the insufflation component 21 in conjunction with the first part ofthe method and the separation component 1 for dissecting the first andsecond tissue layers, however, the second part of the method and theinsufflation component 21 may be used in conjunction with any otherdissection method or apparatus including manual dissection with anendoscope, graspers, operating scope or any blunt instrument which maybe used to dissect the tissue layer by sweeping the area between thelayers.

An obturator 33, having a blunt tip 59, is preferably inserted throughthe flapper valve 32 in the port 25 into the bore of the inner tube 35.The tip of the obturator projects beyond the distal end of the innertube to provide the insufflation component 21 with a blunt nose. Theblunt nose enables the distal end of the insufflation component to beatraumatically inserted into the properitoneal space through theincision I. The insufflation component is advanced through the incisionuntil the proximal end of the cylindrical envelope 45 is in theproperitoneal space, clear of the incision, as shown in FIG. 3F.

A suitable source (not shown) of an inflation fluid is attached to thesecond valve 53. A gas, such as air or carbon dioxide, can be used forthe inflation fluid; alternatively, a liquid, such as saline can beused. Since the volume of inflation fluid required to inflate thetoroidal inflatable chamber is small, about 15 ml in the preferredembodiment, the inflation fluid can be forced into the toroidalinflatable chamber from a large syringe. Inflation fluid is fed into thetoroidal inflatable chamber 43 to expand the toroidal inflatable chamberto its expanded condition, as shown in FIG. 3G.

The anchor flange 55 is then advanced in the direction of the arrow 59along the outer tube 37 to bring the anchor flange into contact with theskin S of the abdominal wall AW. The insufflation component 21 is thengripped, and the anchor flange is further advanced slightly. This forcesthe expanded toroidal inflatable chamber 43 into contact with theunderlying layer, and slightly compresses the abdominal wall, includingthe underlying layer, but excluding the peritoneum P, between thetoroidal inflatable chamber and the anchor flange. Once adjusted, theanchor flange is locked in position on the outer tube. The expandedtoroidal inflatable chamber is held against the underlying layer, andforms a gas-tight seal between the insufflation component and theabdominal wall, including the underlying layer, excluding theperitoneum.

A suitable source (not shown) of an insufflation gas is attached to thefirst valve 31, and insufflation gas is passed through the bore of theinner tube 35 into the working WS space between the peritoneum P and theunderlying layer created by separating by the peritoneum from theunderlying layer using the separation component of the apparatus in thefirst part of the method described above. The pressure of theinsufflation gas re-separates the peritoneum from the underlying layer,as shown in FIG. 3H, and provides a working space in which repair of thehernia can be carried out. The obturator is removed from the bore of theinner tube 35. The bore of the inner tube 35 can then be used to passinstruments, such as the endoscope E, into the working space to performthe repair procedure. Insufflation pressure is maintained by the flappervalve 32.

As part of the hernia repair procedure, additional gas-tight trocarsheaths are inserted through the abdominal wall into the working spaceWS, shown in FIG. 31. An endoscope (not shown) can be passed into theworking space through the bore of the inner tube 35, or through one ofthe additional trocar sleeves for observation. If the properitoneal fatlayer FL remains attached to the properitoneal fascia F, it is scrapedoff the fascia around the site of the hernia so that the patch can beattached directly to the fascia.

A patch M, preferably a Dacron® or Teflon® mesh, is shown gripped by thegrippers G, and passed through the trocar sleeve TS2 into the workingspace. Using the grippers, the patch is manipulated to place it incontact with the properitoneal fascia F over the site of the hernia. Thepatch is attached to the properitoneal fascia by staples inserted usingthe stapler ST passed through the trocar sleeve TS1 into the workingspace. Sutures can alternatively be used to attach the patch to theproperitoneal fascia.

After the treatment procedure is completed, the first valve 31 isoperated to release the insufflation gas from the working space. Thesecond valve 53 is operated to release the inflation fluid from thetoroidal inflatable chamber 43. The envelope 45 of the toroidalinflatable chamber returns to its collapsed state, flush with the outersurfaces of the inner tube and the outer tube. The insufflatingcomponent is then withdrawn from the incision, and the incision isclosed using sutures or clips. The pressure of the viscera against theperitoneum returns the peritoneum into contact with the underlyinglayer. Over time, the peritoneum reattaches to the underlying layer.

2. First One-Component Apparatus

(a) Main Embodiment

The separation component can be dispensed with, and the insufflationcomponent can be modified to provide the first embodiment of a onecomponent apparatus according to the invention. The first one-componentapparatus is shown in FIG. 4A. The first one-component apparatus 121 issimilar to the insufflation component just described. Like componentswill use the same reference numbers with 100 added. The first onecomponent apparatus comprises a tube assembly 160, including an innertube 135 coaxially mounted inside an outer tube 137. The outer tubecovers the inner tube over most of the length of the inner tube. Theinner tube is a rigid tube having a bore with a circular cross sectionthat can accommodate an endoscope (not shown).

The proximal end of the inner tube 135 is fitted with a port 125, theproximal end 127 of which includes a flapper valve 132. The shutter 136of the flapper valve is operated by the button 129. Additionally, theseat 134 of the flapper valve forms a gas-tight seal with an endoscope(not shown), or other instrument, inserted though the flapper valve intothe bore of the inner tube 135. The port 125 is also fitted with a firstvalve 131 to which a supply of a suitable insufflation fluid can beconnected.

Unlike the insufflator component of the two-component apparatus, thedistal end 141 of the outer tube 137 extends as far as the distal end139 of the inner tube 135. The tubes are connected together over adistal portion 167 of their lengths (see detail in FIG. 4B). Acircumferential groove 169 is formed in the inner wall of the distalportion 167. A groove with a wedge-shaped cross section is shown. Thecircumferential groove can have other cross sections, such as square, orsemi-circular. The circumferential groove retains the main envelope 112,which defines the main inflatable chamber 113, in the bore of the innertube, as will be described in more detail below.

The envelope 145 of the toroidal inflatable chamber 143 covers thedistal part of the tube assembly 160. The envelope 145 is a cylindricalpiece of a thin elastomeric material, such a latex, silicone rubber, orpolyurethane. The proximal end 147 and the distal end 149 of theenvelope are attached to the outer surface 163 of the tube assemblyusing a circumferential line of adhesive applied at each end of theenvelope. An epoxy or cyanoacrylate adhesive is preferably used. Whenthe toroidal inflatable chamber is in its collapsed state, the envelope145 lies almost flush with the outer surface of the tube assembly 160.

The outer tube 137 is spaced from the inner tube 135 over at least partof its circumference. The space 151 between the inner tube and the outertube, and a radial passage 161 through the wall of the outer tubeinterconnect the toroidal inflatable chamber 143 and the second valve153. The second valve 153 is connected to a source of a suitableinflation fluid (not shown). The toroidal inflatable chamber is shown inits collapsed state in FIGS. 4A and 4B, and in its expanded state inFIG. 4C.

The anchor flange 155 is slidably mounted on the tube assembly 160, andcan be locked in a desired position along the length of the tubeassembly with a simple over center action locking lever (not shown). Aswill be described in detail below, the anchor flange and the toroidalinflatable chamber, in its expanded condition, form a gas-tight seal toprevent insufflation gas from escaping.

The first one-component apparatus also includes a main envelope 112detachably attached to the bore of the inner tube 135. The main envelopedefines the main inflatable chamber 113. The main envelope is preferablyformed of an elastomeric material such as latex, silicone rubber, orpolyurethane. The main envelope can also be formed from a thin,inelastic material such as Mylar®, polyethylene, nylon, etc. If aninelastic material is used, it should be suitably packaged to fit insidethe bore of the inner tube when in its collapsed state.

The main envelope 112 is formed such that it has a substantiallyspherical shape when it is in its expanded state, and is also formedwith a neck 165. The neck has an outside diameter substantially equal tothe diameter of the bore of the inner tube 135. The neck 165 can berolled outwards a number of times, as in the neck of a common toyballoon, or the neck can be attached to a suitable O-ring 171, as shownin FIG. 4B. The rolled neck, or the O-ring attached to the neck, engageswith the circumferential groove 169 in the inner wall in the inner tubeto attach the main envelope 112 to the inner tube. The main envelope ishoused in the bore of the inner tube when the main inflatable chamber isin its collapsed state.

The rip cord 173 is attached to the neck 165 of the main envelope 112,runs proximally up the bore of the inner tube 135, and emerges from theport 125 through the flapper valve 132. The part of the rip cord 173emerging from the flapper valve can be gripped and pulled in a proximaldirection to release the rolled neck 165 or the O-ring 171 from thecircumferential groove 169. By pulling further on the rip cord, theentire main envelope can be pulled proximally through the bore of theinner tube.

(b) Alternative Embodiment

An alternative embodiment of the first one-component apparatus having anelongated main envelope 112A is shown in FIG 5A. The tube assembly 160Aincludes the inner tube 135A mounted coaxially inside the outer tube137A, with the proximal and distal ends of the tubes interconnected. Thespace 151A between the inner tube and the outer tube communicates withthe toroidal inflatable chamber through the radial passage 161A in thewall of the outer tube. The space between the inner tube and the outertube also communicates with the toroidal chamber inflation valve 153A.

The bore of the inner tube 135A communicates with the port 125A, fittedwith the insufflation valve 185. The port 125A is also fitted with aflapper valve 132A, including the flapper valve seat 134A, whichmaintains gas pressure when the apparatus is used for insufflation. Theflapper valve seat 134A also provides a gas-tight seal around anyinstrument, such as the endoscope E, passed through the flapper valve.

The elongated main envelope 112A is shown in FIG. 5B. The main envelopeis an elongated cylinder with a closed distal end 177. The main envelopeis preferably formed from an elastomeric material, such as latex,silicon rubber, or polyurethane. Attached to the proximal end of themain envelope is a manifold 175 which mates with the proximal face 127Aof the port 125A. The manifold 175 is fitted with an O-ring seal 187,which forms a gas-tight seal with any instrument passed through it. Themanifold 175 is also fitted with the main chamber inflation valve 131 Ato which a supply (not shown) of a suitable inflation fluid can beattached to inflate the main inflatable chamber 112A.

The elongated main envelope 112A is passed through the flapper valve132A into the bore of the inner tube 135A. The manifold 175 is engagedwith the proximal face 127A of the port 125A. When the manifold isengaged, the distal end 177 of the main envelope projects beyond thedistal end of the tube assembly 160A, as shown in FIG. 5C. The distalend of the main envelope is then inverted into the bore of the innertube 135A, as shown in FIG. 5D.

An endoscope, or some other suitable instrument, is inserted through theO-ring seal 187 to seal the manifold before inflation fluid is passedthrough the main chamber inflation valve 131A to inflate the maininflatable chamber 113A.

Alternatively, the seal 187 can be replaced by an additional flappervalve (not shown) so that the main inflatable chamber can be inflatedwithout the need to use an instrument to seal the manifold.

When inflation fluid is passed into the main inflatable chamber 113Athrough the valve 131A, the distal end 177 of the main envelope 112A isejected from the inner tube 135A. The inflation fluid then progressivelyexpands the main envelope 112A, and hence the main inflatable chamber113A defined by the main envelope, into an expanded state, as shown inFIG. 5A. The part of the main envelope inside the inner tube is subjectto the same inflation pressure as the distal end 177 of the mainenvelope, but is constrained by the inner tube and so does not inflate.

After using the main envelope 112A to separate the peritoneum away fromthe underlying layer, as will be described in detail below, theinflation pressure fluid is vented from the main inflatable chamber113A, and the main envelope returns to its collapsed state. When themain envelope is in its collapsed state, it can move freely in the boreof the inner tube 135. The main envelope is removed from the inner tubeby disengaging the manifold 175 from the proximal face 127A of the port125A, and using the manifold 175 to pull the main envelope proximallythrough the bore of the inner tube.

Inflation fluid for the toroidal inflatable chamber the envelope ofwhich 145A is shown in FIG. 5A, is passed through the toroidal chamberinflation valve 153A. Insufflation gas is passed through theinsufflation valve 185.

The toroidal inflatable chamber and the anchor flange 155A of thealternative embodiment of the first one-component apparatus are the sameas in the main embodiment, and will therefore not be described.

(c) Method of Using the First One-Component Apparatus (Both Forms)

The method according to the invention of using either form of the firstone-component apparatus according to the invention to separate a firstlayer of tissue from a second layer of tissue will next be described. Asan illustration, separating the peritoneum from the properitoneal fasciain the course of repairing a hernia will be described.

FIGS. 6A through 6H show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm. long is made in the abdominal wallAW, and carried through the abdominal wall as far as, and including theproperitoneal fat layer FL, as shown in FIG. 6A. The distal end 115 ofthe tube assembly 160 of the one-component apparatus 121 is theninserted into the incision to bring the distal end into contact with theperitoneum. Additional gentle pressure detaches the part of theperitoneum in the immediate vicinity of the incision from the underlyinglayer, as shown in FIG. 6B. FIG. 6B shows the peritoneum detached fromthe properitoneal fat layer FL. The main envelope cannot be seen inthese figures because it is inverted within the bore of the tubeassembly.

A source of inflation fluid (not shown) is connected to the valve 131. Agas, preferably air, is the preferred inflation fluid, but other gases,such a carbon dioxide can be used. A liquid, such as saline solution canbe used, but liquids are less preferable to gases because they changethe optical properties of any endoscope inserted into the maininflatable chamber 113. The flow of inflation fluid is turned on, whichejects the main envelope 112 from the bore of the tube assembly 160.

The inflation fluid progressively expands the main envelope 112, andhence the main inflatable chamber 113 defined by the main envelope, intoan expanded state. The main envelope expands between the peritoneum Pand the properitoneal fat layer FL, and gently and progressivelydetaches an increasing area of the peritoneum from the underlying layeras it expands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4″-6″ (100-150 mm) in diameter.

Early in the process of expanding the main envelope 112, an endoscope Eis inserted into the flapper valve 132 in the port 125, as shown in FIG.6C. The endoscope E is passed through the bore of the tube assembly 160into the main inflatable chamber 113. Once the main envelope ispartially expanded, the main envelope is sufficiently transparent forthe extent of the detachment of the peritoneum to be observed using theendoscope.

When a sufficient area of the peritoneum is detached, the supply ofinflation fluid is turned off. The inflation fluid is then vented fromthe main inflatable chamber 113, and the main envelope progressivelyreturns to its collapsed state. The peritoneum remains detached from theunderlying layer, however, as shown in FIG. 6D. The main envelope isthen removed from the bore of the tube assembly 160. The differentmethods of removing the main envelope from the bore of the tube assemblyfor the two different forms of the first one-component apparatus aredescribed above.

After the main envelope 112 has been removed from the bore of the tubeassembly, the tube assembly is advanced into the incision in thedirection of the arrow 162 until the proximal end of the envelope 145 ofthe toroidal inflatable chamber is in the properitoneal space, clear ofthe incision, as shown in FIG. 6E.

A suitable source (not shown) of an inflation fluid is attached to thevalve 153. A gas, such as air or carbon dioxide, can be used for theinflation fluid; alternatively, a liquid, such as saline can be used.Since the volume of inflation fluid required to inflate the toroidalinflatable chamber is small, about 15 ml in the preferred embodiment,the inflation fluid can be contained in a large syringe. Inflation fluidis fed into the toroidal inflatable chamber 43 to expand the toroidalinflatable chamber to its expanded condition, as shown in FIG. 6F.

The anchor flange 155 is then advanced in the direction of the arrow 159along the tube assembly 160 to bring the anchor flange into contact withthe skin S of the abdominal wall AW. The tube assembly 160 is thengripped, and the anchor flange is further advanced slightly. This forcesthe expanded toroidal inflatable chamber 143 into contact with theunderlying layer, and slightly compresses the abdominal wall AW,including the underlying layer but excluding the peritoneum P, betweenthe expanded toroidal inflatable chamber and the anchor flange, as shownin FIG. 6G. Once adjusted, the anchor flange is locked in position onthe tube assembly. The expanded toroidal inflatable chamber is heldagainst the underlying layer and forms a gas-tight seal with theabdominal wall, excluding the peritoneum.

A suitable source (not shown) of an insufflation gas is attached to thefirst valve 131, and insufflation gas is passed through the bore of theinner tube 135 into the working space WS between the peritoneum P andthe underlying layer created by separating the peritoneum from theunderlying layer. The pressure of the insufflation gas re-separates theperitoneum from the underlying layer, as shown in FIG. 6H, and providesa working space in which repair of the hernia can be carried out. Thebore of the tube assembly 160 can be used to pass instruments, such asthe endoscope E, into the working space to perform the repair procedure.When no instrument is inserted into the bore of the tube assembly,insufflation pressure is maintained by the flapper valve.

As part of the hernia repair procedure, additional gas-tight trocarsleeves (not shown) are inserted through the abdominal wall into theworking space. The same procedure as described above in connection withFIG. 3I is used to attach a mesh patch to the properitoneal fascia overthe site of the hernia. The process can be observed with the aid of anendoscope (not shown) passed through the bore of the tube assembly 160,or through one of the additional trocar sleeves.

After the treatment procedure is completed, the valve 131 is operated torelease the insufflation gas from the working space WS. The valve 153 isoperated to release the inflation fluid from the toroidal inflatablechamber 143, which releases compression of the abdominal wall AW,excluding the peritoneum. The toroidal inflatable chamber returns to itscollapsed state, with its envelope 145 flush with the outer surface thetube assembly 160. The tube assembly is then withdrawn from theincision, and the incision is closed using sutures or clips. Thepressure of the viscera against the peritoneum returns the peritoneuminto contact with the underlying layer. Over time, the peritoneumreattaches to the underlying layer.

3. Second One-Component Apparatus

(a) Second One-Component Apparatus

A second embodiment of a one-component apparatus is shown in FIGS. 7Aand 7B. The second one-component apparatus 121 is similar to the firstone-component apparatus just described. However, the secondone-component apparatus has a substantially spherical toroidal maininflatable chamber, that avoids the need to detach and remove the mainenvelope at the end of the separation process. Also, in the secondone-component apparatus, a single toroidal main inflatable chamberprovides the separating function of the main inflatable chamber and thesealing function of the toroidal inflatable chamber of the firstone-component apparatus.

In the following description, similar components will use the samereference numbers with an additional 100 added.

The second one-component apparatus comprises a tube assembly 260,including an outer tube 237 to which is attached a twin port assembly224 is attached. The port assembly includes a first port 226 and asecond port 228. The first port is provided with a first flapper valve202, including the flapper valve seat 204. The second port is providedwith a second flapper valve 206, including the flapper valve seat 208.Each flapper valve seat additionally forms a gas-tight seal with aninstrument passed through it.

The tube assembly 260 also includes the inner tube 235. The inner tubehas a length that is shorter than the length of the outer tube 237. Theproximal end 210 of the inner tube is flexibly attached to the proximalend 222 of the outer tube 237 and to the first port 226. The flexibleattachment enables the distal end 214 of the inner tube to move in thedirection shown by the arrow 216. The first port communicates with thebore of the inner tube 235, and the second port communicates with thebore of the outer tube 237.

The insufflation valve 285 communicates with the first port 226, and thebore of the inner tube 235. The main chamber inflation valve 231communicates with the second port 228, and the bore of the outer tube237.

The main envelope 212 defines the main inflatable chamber 213 andcomprises a cylindrical piece of an elastomeric material such a latex,silicone rubber, or polyurethane. The apparatus is shown with its mainenvelope in its collapsed state in FIG. 7B, in which the structure ofthe main envelope can also be seen. The main envelope preferably has adiameter smaller than the outside diameter of the inner tube. One end230 of the main envelope is attached to the distal end 214 of the innertube 235 by means of a suitable adhesive, such as an epoxy orcyanoacrylate adhesive. The other end 232 of the main envelope iseverted (i.e., turned back on itself to bring the inside surface 234 ofthe main envelope to the outside) and attached to the distal end 236 ofthe outer tube using the same type of adhesive. The main envelope ispreferably attached to the outer surfaces of the inner tube and theouter tube.

The apparatus is shown with the main envelope 212 in its expanded statein FIG. 7A. A suitable source of inflation gas is connected to the valve231 and flows into the main inflatable chamber through the bore of theouter tube 237. The pressure acting on the surface 238 of the mainenvelope 212 causes the main envelope to assume the toroidal shape shownin FIG. 7A to define the toroidal main chamber 213. FIGS. 7A and 7B showthe correspondence between the surfaces 234 and 238 of the main envelopewhen the main envelope is in its collapsed state (FIG. 7B) and in itsexpanded state (FIG. 7A).

The anchor flange 255 is slidably mounted on the tube assembly 260, andcan be locked in a desired position along the length of the tubeassembly. The anchor flange 255 is similar to the anchor flange 55 (FIG.2A) and so will not be described further.

In FIG. 8A, an endoscope E is shown passed through the second flappervalve 206, the second port 228, and the bore of the outer tube 237 intothe main inflatable chamber 213. The flexible mounting of the inner tube235 in the outer tube enables the endoscope to displace the inner tube235 in direction of the arrow 216 to gain access to the main inflatablechamber. The endoscope is inserted through the second port into the maininflatable chamber during the separation phase of using the apparatus toobserve the extent of the separation of tissue.

In FIG. 8B, an endoscope E is shown passed through the first flappervalve 202, the first port 226, the bore of the inner tube 235, and thebore 234 of the main envelope 212. The distal part of the endoscopeemerges from the bore of the main envelope, and can be advanced beyondthe main inflatable chamber 213 to observe the site of the hernia moreclosely. The endoscope is inserted through the first port, the innertube, and the bore of the main envelope during the insufflation phase ofusing the apparatus. Instruments other than endoscopes can also bepassed to the site of the hernia through the first flapper valve, thefirst port, the inner tube, and the bore of the main envelope ifdesired.

Also in FIG. 8B, the main envelope 212 is shown in the partiallycollapsed state that it preferably assumes during the insufflation phaseof the procedure. In this part of the procedure, the partially collapsedmain inflatable chamber and the anchor flange 255 together provide agas-tight seal to prevent the leakage of insufflation gas.Alternatively, this part of the procedure can be carried out with themain inflatable chamber in a fully expanded state.

Method of Using the Second One-Component Apparatus

The method according to the invention of using the second embodiment ofthe one-component apparatus according to the invention to separate afirst layer of tissue from a second layer of tissue will next bedescribed. As an illustration, separating the peritoneum from theproperitoneal fascia in the course of repairing a hernia will bedescribed.

FIGS. 9A through 9F show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm long is made in the abdominal wallAW, and carried through the abdominal wall as far as, and including, theproperitoneal fat layer FL, as shown in FIG. 9A. The distal end 215 ofthe tube assembly 260 of the second one-component apparatus 221 is theninserted into the incision to bring the distal end into contact with theperitoneum P. Additional gentle pressure detaches the part of theperitoneum in the immediate vicinity of the incision from the underlyinglayer, as shown in FIG. 9B. FIG. 9B shows the peritoneum detached fromthe properitoneal fat layer FL. The main envelope cannot be seen inthese figures because it is inverted within the bore of the tubeassembly.

A source of inflation fluid (not shown) is connected to the valve 231. Agas, preferably air, is the preferred inflation fluid, but other gases,such a carbon dioxide can be used. A liquid, such as saline solution canbe used, but liquids are less preferable to gases because they changethe optical properties of any endoscope inserted into the maininflatable chamber. The flow of inflation fluid is turned on, whichejects the main envelope 212 from the bore of the tube assembly 260.

The inflation fluid progressively expands the main envelope 212, andhence the main inflatable chamber 213 defined by the main envelope, intoan expanded state. The main envelope expands between the peritoneum Pand the properitoneal fat layer FL, and gently and progressivelyseparates an increasing area of the peritoneum from the underlying layeras it expands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4″-6″ (100-150 mm) in diameter.

Early in the process of expanding the main envelope 212, an endoscope Eis inserted into the first flapper valve 202, as shown in FIG. 9C. Theendoscope E is passed through the bore of the outer tube 237 into themain inflatable chamber 213. Once partially expanded, the main envelope212 is sufficiently transparent for the extent of the separation of theperitoneum to be observed using the endoscope.

When a sufficient area of the peritoneum is separated, the supply ofinflation fluid is turned off. The endoscope E is removed from the maininflatable chamber 213. The valve 231 is then opened to allow inflationfluid to vent partially from the main inflatable chamber 213. The mainenvelope 212 progressively returns part-way towards its collapsed state,as shown in FIG. 9D. Alternatively, the main envelope may be kept fullyexpanded.

The anchor flange 255 is then advanced in the direction of the arrow 259along the tube assembly 260 to bring the anchor flange into contact withthe skin S of the abdominal wall AW. The tube assembly 260 is thengripped, and the anchor flange is further advanced slightly. This forcesthe main inflatable chamber 213 into contact with the underlying layer,and slightly compresses the abdominal wall, including the underlyinglayer but excluding the peritoneum, between the main inflatable chamberand the anchor flange, as shown in FIG. 9E. Once adjusted, the anchorflange is locked in position on the tube assembly. The main inflatablechamber is held against the underlying layer and forms a gas-tight sealwith the abdominal wall, excluding the peritoneum.

A suitable source (not shown) of insufflation gas is attached to thesecond valve 285, and insufflation gas is passed through the bore of theinner tube 235, and the bore 234 of the main envelope, into the workingspace WS between the peritoneum P and the underlying layer. The pressureof the insufflation gas re-separates the peritoneum from the underlyinglayer, as shown in FIG. 9F, and provides a working space in which repairof the hernia can be carried out.

Instruments, such as the endoscope E, can be passed through the secondflapper valve 206, the bore of the inner tube 235, and the bore 234 ofthe main envelope, as shown in FIG. 8B, into the working space toperform the repair procedure. When no instrument is inserted into thebore of the inner tube, insufflation pressure is maintained by thesecond flapper valve.

As part of the hernia repair procedure, additional gas-tight trocarsleeves (not shown) are inserted through the abdominal wall into theworking space. The same procedure as described above in connection withFIG. 3I is used to attach a mesh patch to the properitoneal fascia overthe site of the hernia. The process can be observed with the aid of anendoscope (not shown) passed into the working space through the bore ofthe inner tube 235, or through one of the additional trocar sleeves.

After the treatment procedure is completed, the valve 285 is operated torelease the insufflation gas from the working space. The valve 231 isoperated to release the inflation fluid from the main inflatable chamber213, which releases compression from the abdominal wall, excluding theperitoneum. The main envelope returns to its collapsed state inside thebore of the outer tube 237.

The tube assembly is then withdrawn from the incision, and the incisionis closed using sutures or clips. The pressure of the viscera againstthe peritoneum returns the peritoneum into contact with the underlyinglayer. Over time, the peritoneum reattaches to the underlying layer.

4. Hernia Repair Method With Incision at the Umbilicus

The hernia repair methods described so far show the incision placedclose to the site of the hernia. In practice, it is preferred to makethe incision at or near the umbilicus because the boundary between theperitoneum and the properitoneal fat layer can be more directly accessednear the umbilicus. The midline location of the umbilicus is devoid ofmuscle layers that would otherwise need to be traversed to reach theproperitoneal fat layer.

Apparatus of the types described above inserted through an incision atthe umbilicus would require a very large main inflatable chamber todetach the peritoneum from the umbilicus to the groin. Instead, in themethod according to the invention to be described next, an apparatus ofany one of the types described above is used to provide a tunnel from anincision at the umbilicus to the site of the hernia in the groin, andthen to provide an insufflated working space at the site of the hernia.

The main envelope is partially expanded, collapsed, and advanced towardsthe site of the hernia. This sequence is repeated to progressivelyseparate the peritoneum from the underlying layer and form the tunnelfrom the umbilicus to the site of the hernia. Then, at or near the siteof the hernia, the main envelope is fully expanded to provide theworking space at the site of the hernia. The working space is theninsufflated to maintain the separation of the peritoneum from theunderlying layer.

The following method can be practiced using the two-component embodimentof the apparatus, or any of the one-component embodiments of theapparatus. The method will be described using the two-componentapparatus.

An incision about 12-15 mm long is made in the abdominal wall AW, and iscarried through the abdominal wall as far as, and including, theproperitoneal fat layer FL. The incision is made at the umbilicus U, asshown in FIG. 10A.

The distal end 15 of the introducer tube 3 of the separation component 1is then inserted into the incision to bring the distal end into contactwith the peritoneum P. Additional gentle pressure detaches the part ofthe peritoneum in the immediate vicinity of the incision from theunderlying layer, as shown in FIG. 10B. In FIG. 10B, the peritoneum isshown detached from the properitoneal fat layer FL. The main envelopecannot be seen in these figures because it is inverted within the boreof the introducer tube 3.

A source of a suitable inflation fluid (not shown), as previouslydescribed, is connected to the valve 11. The flow of inflation fluid isturned on, which ejects the main envelope 12 of the main inflatablechamber 13 from the bore of the introducer tube 3. The inflation fluidprogressively expands the main envelope 12, and hence the maininflatable chamber 13 defined by the main envelope, into apartially-expanded state, as shown in FIG. 10C. The main envelopeexpands between the peritoneum and the properitoneal fat layer FL, andgently and progressively detaches an increasing area of the peritoneum Pfrom the underlying layer near the umbilicus as it expands.

An endoscope (not shown) can be inserted into the main inflatablechamber 13 through the flapper valve 2 and the bore of the introducertube 3. The endoscope can be used to observe the extent of theseparation of the peritoneum, as described above.

When the main envelope 12 expanded such that the main inflatable chamber13 is about one-fourth of its fully-expanded diameter, i.e., about1.0″-1.5″ (25-37 mm) in diameter, the supply of inflation fluid isturned off. The valve 11 is then operated to vent inflation fluid fromthe main inflatable chamber 13. The main envelope progressively returnsto its collapsed state, as shown in FIG. 10D. The peritoneum DP that wasseparated by the main inflatable chamber remains detached from theunderlying layer, however, as shown. Alternatively, the main envelopecan be inflated to a fully-expanded state.

The separation component 1, including the collapsed main envelope 12, isthen manipulated in the direction indicated by the arrow 14, and then inthe direction indicated by the arrow 16, to advance the distal part 15of the introducer tube 3 to the limit of the detached part of theperitoneum DP in the direction of the groin, as shown in FIG. 10E. Anendoscope E inserted through the flapper valve 2 into the bore of theintroducer tube 3 enables the position of the distal part of theintroducer tube relative to the detached part of the peritoneum to beobserved.

Once the distal part 15 of the introducer tube has been positioned, theseparation component 1 is clamped in position, or is gripped, andinflation fluid is once more passed through the valve 11, and the boreof the introducer tube 3 into the main inflatable chamber 13. The mainenvelope 12 expands once more, increasing the extent of the detachedpart of the peritoneum towards the groin, as shown in FIG. 10F. Theincreased extent of the detached part of the peritoneum is indicated bythe line DP′ in the figure. It should be noted that the extent of thedetached part of the peritoneum is increased in the direction from theumbilicus to the groin, but not in the direction transverse to thisdirection. The endoscope E is used to observe the extent of theseparation.

The process of collapsing the main envelope 12, advancing the distalpart 15 of the introducer tube to the limit of the detached part of theperitoneum DP, in the direction of the groin, holding the introducertube in position, and partially re-inflating the main envelope 12, isrepeated until the detached part of the peritoneum includes theperitoneum over the site of the hernia. This process provides the tunnelT between the incision at the umbilicus and the site of the hernia. Thiscan be seen in FIG. 10I. Alternatively, the main envelope can be fullyre-inflated.

When the main envelope is in the vicinity of the site of the hernia H,the main envelope 12 is fully inflated to form a working space WSincluding the site of the hernia. This is shown in FIG. 10G.

The working space at the site of the hernia is then insufflated. Withthe two-component apparatus, inflation fluid is vented from the maininflatable chamber 13 to collapse the main envelope 12, and theseparation component 1 is withdrawn from the tunnel T through theincision I. The insufflation component 21 is introduced into theincision, and advanced through the tunnel until the envelope 45 of thetoroidal inflatable chamber 43 lies within the working space WS, clearof the tunnel. The toroidal inflatable chamber is inflated, the anchorflange is clamped in position, and insufflation gas is passed into theworking space, as shown in FIG. 10H. The toroidal inflatable chamberprovides a gas-tight seal with the entrance of the tunnel.

FIG. 10I shows a plan view of the abdomen with the insufflator component21 in place. The anchor flange has been omitted for clarity. Thetoroidal inflatable chamber 43 provides a gas-tight seal with theentrance of the tunnel T. The extent of the separated peritoneum isindicated by the dotted line DP. It can be seen that the lateral extentof the separated peritoneum is considerably greater in the working spaceWS than in the tunnel T.

With the first embodiment of the one-component apparatus, inflationfluid is vented from the main inflatable chamber to collapse the mainenvelope, and the main envelope is withdrawn from the working spacethrough the bore of the tube assembly. The tube assembly is partiallywithdrawn until the envelope of the toroidal inflatable chamber lieswithin the working space, clear of the entrance to the tunnel. Thetoroidal inflatable chamber is inflated, the anchor flange is clamped inposition and insufflation gas is passed into the working space, asalready described. The toroidal inflatable chamber seals against theentrance from the tunnel into the working space.

Using the second embodiment of the one-component apparatus, the mainenvelope is preferably returned to a partially collapsed state, the tubeassembly is partially withdrawn until the main inflatable chamber lieswithin the working space, adjacent to the entrance of the tunnel. Theanchor flange is clamped in position, and insufflation gas is passedinto the working space, as already described. The partially-collapsedmain chamber seals against the entrance from the tunnel into the workingspace.

If the main envelope is inflated to a fully expanded state during theseparation part of the procedure, the whole of the space is insufflatedwith a gas-tight seal at the incision, as previously described.

Irrespective of the embodiment of the apparatus used to create theinsufflated working space WS, the hernia is then repaired using theprocedure described in connection with FIG. 3I.

5. Inflatable Chambers for Maintaining Separation of Tissue Layers

As previously discussed, during dissection of the properitoneal space orduring subsequent surgical procedures near the peritoneum, it is commonto puncture or otherwise breach the peritoneum. Such a puncture orbreach prevents the properitoneal space from retaining pressurized fluid(gas or liquid) used to maintain the space in an open condition. Ifpressure is lost, visualization of the space and the actual volume ofthe space will decrease and compromise the surgery. Absent some way ofmechanically maintaining the space, loss of pressure can result ininability to complete the procedure.

An additional consideration in laparscopic surgery inside the peritonealspace is fouling of the distal end of the endoscope with body fluidscaused by incidental contact with either tissues near the entry point ofthe endoscope or tissues near the distal end of the cannula throughwhich the endoscope has been inserted.

(a) First Inflatable Chamber

Referring to FIGS. 11A and 11B, an insufflation and retraction device301 having a first inflatable chamber 303 is shown. The insufflation andretraction device 301 is similar to the insufflation component 21 of thetwo-component apparatus, shown in FIGS. 2D and 2E, and like referencenumerals represent like components. It is understood that although it ispreferred to use the inflatable chambers described below with theinsufflation and retraction device 301, the inflatable chambers may alsobe used with any other delivery or inflation device.

The insufflation and retraction device 301 includes an inner tube 335and a coaxial outer tube 337. The distal end 323 of the inner tube 335extends beyond the distal end 325 of the outer tube 337. The inner tube335 is similar to the introducer tube 3 (FIG. 2A) and is a rigid tubehaving a bore with a circular cross section that can preferablyaccommodate a 10 mm endoscope, however, any cross-sectional shape orarea may be provided. The proximal end of the inner tube 335 is fittedwith a flapper valve as described above in connection with theinsufflation component of FIGS. 2D and 2E. A seat at the proximal end ofthe inner tube forms a gas-tight seal with an appropriately sizedinstrument. A shutter covers the seat and is operated by a button 329. Ablunt obturator 322 is shown extending through the seat and through thedistal end 323 of the inner tube 335 (FIGS. 11A and 11B). A valve 331 isfluidly coupled to the interior of the inner tube 335 and may be used tosupply insufflation gas or liquid.

The first inflatable chamber 303 has a distal side 343 coupled to theinner tube 335 and a proximal side 345 coupled to the outer tube 337 sothat the interior of the inflatable chamber 303 is fluidly coupled tothe annular space between the inner and outer tubes 335, 337. Theproximal and distal sides 345, 347 of the inflatable chamber 303 arepreferably attached to the inner and outer tubes 335, 337 at flanges359. A valve 353 is adapted to be connected to a source of a suitableinflation gas or liquid (not shown) for inflating the inflatable chamber303. The inflatable chamber 303 is shown in a collapsed state in FIG.11A and in an expanded state in FIGS. 11B and 11C.

An anchor flange 355 is slidably mounted to the outer tube 337 and canbe locked along the length of the outer tube 337 with a locking lever349. The anchor flange 355 helps to immobilize the device and, further,helps the inflatable chamber 303 form a seal to limit the escape ofinsufflation gas during laparoscopic procedures. When the anchor flange355 is locked into position, the anchor flange 355 and inflatablechamber 303 apply a modest compressive force to the tissue between theinflatable chamber 303 and the anchor flange 355 thereby improving thegas-seal.

Referring to FIG. 11A, the inflatable chamber 303 is folded andcontained within a sheath 349 before insertion into a patient. Theinflatable chamber 303 may be folded in any manner but is preferablyfolded inwardly from lateral, side edges 351, 353 toward the extendeddistal end of obturator 322. The sheath 349 is preferably perforated butmay be formed in any other manner permitting easy opening. Theinflatable chamber 303 is initially in the folded, compact orientationof FIG. 11A before insertion into the patient so that the retractiondevice may be easily inserted through a small opening in the patient. Aswill be described below, after the inflatable chamber 303 has beenpositioned within a patient and between the two tissue layers to beseparated, inflation air is injected into the inflatable chamber 303through the second valve 353. Inflation of the chamber 303 tears thesheath 349 along the perforation 361 and releases the inflation chamber303. Alternatively, the sheath 361 may include an independent openingmechanism, such as a removable thread which binds the sheath together.

Referring to FIG. 11C, the inflatable chamber 303 preferably has asubstantially trapezoidal shape. First and second sides 363, 365 of theinflatable chamber 303 are preferably slightly curved but may also belinear or bi-linear. The first and second sides 363, 365 and lateralsides 351, 353 may also include surface features such as ridges orrounded teeth to help anchor the inflatable chamber 313 and improve theinsufflation gas seal. The second side 365 is preferably longer than thefirst side 363 and forms angles of less than 90 degrees with the lateralsides 351, 353. Furthermore, the inner and outer tubes 335, 337 arepreferably connected to the inflatable chamber 303 closer to the firstside 363 than the second side 365. A throughhole 358 is defined by theouter tube and extends through the first and second sheets. The shape ofinflatable chamber 303 may also be modified and/or optimized to suit theparticular use contemplated. The location and configuration of thethroughhole 358 may also be modified.

The inflatable chamber 303 is formed with first and second sheets 367,369 attached together along a periphery 371. This arrangement results inrelatively high localized stress at the periphery 371 of the first andsecond sheets 367, 369. To withstand this stress, the strength of thesheets must be increased. One way of increasing the strength of thesheets is to increase the thickness of the sheets. A problem with simplyincreasing the sheet thickness is that the inflatable chamber 303becomes larger in the collapsed state (FIG. 11A) which will causes moreproblems during insertion into a patient.

To alleviate the problem of localized stresses without increasing thesheet thickness, the present invention provides baffles 373 disposedbetween the first and second sheets 367, 369. The baffles 373interconnect the first and second sheets 367, 369 and help absorb thepressure forces thereby reducing stresses at the periphery 371. Thebaffles 373 also help define the shape of the inflatable chamber 303 andlimit the separation distance between the first and second sheets 367,369 when the inflatable chamber 303 is in the expanded shape. Thepreferred method of attaching the baffles 373 to the first and secondsheets 367, 369 is described below.

(i) Preferred Material for the Inflatable Chamber

The first and second sheets 367, 369 and baffles 373 are preferably madeof a polyester and polyurethane composite material. Polyester hasdesirable strength characteristics but it is relatively rigid andcrinkles easily. Moreover, polyester is very difficult to RF weld whichis a preferred method of connecting the baffles and sheets together aswill be described below. Polyurethane, on the other hand, is soft,nonabrasive, and easy to RF weld. Unfortunately, the tensile strength ofpolyurethane is relatively low. The composite material exploits theadvantages of both polyester and polyurethane.

The composite material is formed by bonding polyurethane to a nylon orpolyester film having a preferred thickness of about 0.5 to 2 mil.(12-50 μm), although a polyester fabric may also be used. The nylon orpolyester fabric may be a woven fabric or may be composed ofrandomly-oriented fibers. The film or fabric layer is laminated (orcast, captured or encapsulated) between two polyurethane layers toprovide a composite material having a preferred thickness of about 3mil. (75 μm). The resulting composite material is strong, supple,non-abrasive, transparent, and easily RF welded. The composite materialwill also fold with small radius folds so that the inflatable chamber303 can be compacted into a small volume for easy insertion into apatient.

The composite material is relatively inelastic and, therefore, must befolded into the sheath as described above (FIG. 11A). The presentinvention may also be practiced with an elastic material which, whenexpanded, provides the shape of the inflatable chambers of the presentinvention. The composite material is disclosed in co-pending U.S. patentapplication Ser. No. 08/134,573, filed Oct. 8, 1993, which is hereinincorporated by reference.

(ii) Method of Constructing the Inflatable Chamber

The baffles 373 are preferably fabricated and attached to the first andsecond sheets 367, 369 in the manner shown in FIGS. 13A through 13C. Thefirst and second sheets 367, 369 and baffles 373 are cut into thedesired shape and oriented as shown in FIG. 13A with the first andsecond sheets 367, 369 being offset with respect to one another. Thebaffles preferably do not extend completely between the first and secondsides so that all portions of the interior of the inflatable chamber arefluidly coupled together. Alternatively, the baffles 373 may includeopenings to fluidly couple the various portions together. The baffles373 are preferably made of the same material as the first and secondsheets but may also be made of a different material.

Referring to the exploded cross-sectional view of FIG. 13B, RF weldingelectrodes 344, 346 are positioned against the first and second sheets367, 369. RF welding imparts radio frequency energy to the workingpiece. When radio frequency energy is imparted onto polyurethane, themolecules are excited and the polyurethane melts thereby bondingtogether adjacent polyurethane layers together. A suitable release agent305 is applied to either the sheets 367, 369 or baffles 373 to preventformation of RF welds at certain locations. A preferred release agent305 is powdered polyethylene and teflon. Without the releasing agent305, the baffle 373 would be RF welded to both the first and secondsheets 367, 369 on both sides. Application of the release agent 305advantageously enables attaching the baffles 373 to the sheets in asingle welding operation.

The RF welding apparatus is activated to weld the baffles 373 to thefirst and second sheets 367, 369. Adjacent polyurethane layers bond atall locations between the RF welding electrodes 375 except where therelease agent 305 has been applied. The first and second sheets are thendisplaced so that they overlie one another as shown in FIG. 13C. Theresulting baffles 373 have a generally S-shaped configuration-when theinflatable chamber is in the expanded condition. A second RF weldingoperation (not shown) welds the periphery 371 of the first and secondsheets together 367, 369.

(b) Second Inflatable Chamber for Maintaining Separation of TissueLayers

A second inflatable chamber 403 for maintaining separation betweentissue layers is shown in FIGS. 12A and 12B. The second inflatablechamber 403 includes an intermediate weld 405 which reduces pressureinduced stresses at the periphery 471 of the inflatable chamber 403. Theintermediate weld 405 eliminates the need to provide baffles, however,baffles may also be provided if necessary. The intermediate weld 405 ispreferably a semi-circular segment having terminal ends 407 positionedadjacent the periphery 471. An interior area 411 is fluidly coupled tothe remainder of the inflatable chamber 403 via two fluid paths 413 sothat when the inflatable chamber 403 is inflated, the interior area 411is also inflated. The fluid paths 413 are preferably provided betweenthe terminal ends 407 of the intermediate weld 405 and the periphery471; however, the fluid path 413 may be positioned anywhere along theintermediate weld 405. Furthermore, although it is preferred to providetwo fluid paths, any number of paths may be provided.

The periphery 471 of the inflatable chamber 403 is substantiallybell-shaped with the hemispherical interior area 411 protruding slightlyfrom a bottom side 413. The bell-shaped periphery 471 has asemi-circular upper portion 415 which is substantially concentric with athroughhole 417. The remainder of the peripheral wall 471 is shaped likea truncated triangle extending downward from the semi-circular upperportion 415. As previously described, the shape of the inflatablechamber may be modified to suit the particular use contemplated.Materials and construction techniques are as described previously.

(c) Third Inflatable Chamber for Maintaining Separation of Tissue Layers

Referring to FIGS. 14A and 14B, a third inflatable chamber 503 is shownwhich also includes intermediate welds 505. The inflatable chamber 503is advantageously formed from only first and second sheets 567, 569 ofmaterial. The intermediate welds 505 are preferably circular but maytake any other shape. The intermediate welds bond the first and secondsheets 567, 569 together throughout the entire circular area of thewelds. Before insertion into a patient, the inflatable chamber 504 ispreferably folded and contained within a perforated sheath as describedabove in connection with the first inflatable chamber 303.

The inflatable chamber 503 has a substantially trapezoidal shapedperiphery 571. The sides 507, 509, 511, 513 of the inflatable chamberare preferably linear but may also be curved. A first side 507 issmaller than a second side 509 and-the second side preferably forms anangle of between 20 and 90 degrees with the lateral sides 511, 513.

(d) Fourth Inflatable Chamber for Maintaining Separation of TissueLayers

Referring to FIGS. 15A and 15B, a fourth inflatable chamber 603 is shownwhich has the same general features as the second inflatable chamber403, however, inflatable chamber 603 includes first and secondextensions 621, 623 having a space 633 therebetween. The space 633provides clearance for insertion of additional instruments into theworking space while minimizing the risk that the additional instrumentswill pierce the inflatable chamber 603 as described below. A throughhole617 extends through the inflatable chamber 603 which is adapted to beconnected to the insufflation component of FIGS. 11A and 11B or may beconnected to any other delivery or inflating device.

The fourth inflatable chamber 603 is preferably symmetrical about a lineof symmetry 609 passing through the throughhole 617. First and secondperipheral points 625, 627 are located on the line of symmetry 609 withthe first peripheral point 625 being closer to the throughhole 627 thanthe second peripheral point 627. The first and second extensions 621,623 have radially outward points 629, 631. A line 630 passing throughthe center of the throughhole 617 and the radially outward to points629, 631 preferably forms an angle A between 10 degrees and 80 degreeswith respect to a line 632 extending between the throughhole and thefirst peripheral point 625. The extensions are preferablytriangular-shaped with rounded edges but may also take any other shapeso long as the space 633 is provided therebetween. Furthermore, thespace 633 is also preferably triangular shaped but may also besemi-circular, square, or a relatively shallow circular segment.Modifications to the proportions illustrated as well as providingasymmetrical designs are also contemplated to suit the particularapplication.

During laparoscopic surgery, additional instruments are often introducedabove the longitudinal axis of the delivery device. The space 633between the extensions 621, 623 facilitates introduction of additionalinstruments along the longitudinal axis of the delivery device above theinflatable chamber 603 while minimizing the-risk that the additionalinstruments will puncture the inflatable chamber 603.

The inflatable chamber 603 is preferably formed from first and secondsheets 667, 669 of the composite material described above but may beformed in any other manner or with any other materials to provide theextensions 621, 623 and space 633 therebetween. The first and secondsheets 667, 679 are preferably attached together about the periphery 671by RF welding as described above. The first and second sheets 667, 669are also preferably coupled together by an intermediate weld 605. Theinflatable chamber 603 may also be formed with baffles or with a sheetmaterial of sufficient thickness to withstand the stress at theperiphery 671.

(e) Fifth Inflatable Chamber for Maintaining Separation of Tissue Layers

Referring to FIGS. 16A and 16B, a fifth inflatable chamber 703 is shownwhich is an alternative to inflatable chamber 303 of FIGS. 11B through11C. The fifth inflatable chamber 703 may be used with any inflation ordelivery device but is preferably used in connection with theinsufflation component of FIGS. 2D and 2E or FIGS. 11A and 11B.

The fifth inflatable chamber 703 has essentially the same structuralfeatures as the first inflatable chamber 303, however, the inflatablechamber 703 includes a pair of triangular-shaped wings 705. Thetriangular wings 705 provide a wider working space within the patientthan the inflatable chamber 303. The wings 705 may also advantageouslyprovide additional tissue dissection when the chamber 703 is inflated.

Inflatable chamber 703 is preferably made from the same or likematerials as inflatable chamber 303 and, furthermore, is constructedwith baffles 707 in the same manner as inflatable chamber 303.

For the first, second, third, fourth and fifth embodiments of theinflatable chamber described above, it should be recognized that theshape of each embodiment has the common functional benefit ofmaintaining the properitoneal space by retaining the separation of theperitoneum from the overlying tissue in the event of loss of optimalpressurization or when a gasless technique is used.

More specifically, the embodiments each employ a bottom surface whichcontacts the peritoneum and an upper surface that contacts the overlyingfascia. For example, in the first embodiment shown in FIG. 11C, theupper surface can be characterized as side 363 and the lower sidecharacterized as side 365. The physical distance between the upper andlower surfaces causes like separation or the peritoneal layer and fascialayers in the dissected properitoneal cavity. The inflatable chamber canbe dimensionally sized to create optimal separation while limitingpotential trauma to tissue. Furthermore, the location of throughhole 358within the inflatable chamber can be selected to optimize the separationof retracted tissue from an endoscope or other instrument passed throughthroughhole 358. Throughhole 358 thus can be centered or offcenter inthe inflatable chamber as desired. Preferably, throughhole 358 islocated slightly off-center towards the upper surface, but centeredlaterally. Such a location optimizes the desired features of reducingendoscope fouling by body fluids as the scope is passed into throughhole358, and separating the scope from the peritoneum to provide maximumviewing field with a scope through throughhole 358. The reduction offouling is accomplished by displacing the throughhole 358 from the uppersurface, and thus overlying fascia, to minimize potential tissue contactwith throughhole 358 and an endoscope passed through throughhole 358.Likewise, the viewing field is maximized by separating throughhole 358,and thus an endoscope in it, from peritoneum being deflected downward bythe lower surface of inflatable chamber.

6. Hernia Repair Method With Incision at the Umbilicus

The hernia repair method described above in connection with theinsufflation component having the toroidal inflatable chamber will knowbe described with respect to the fourth inflatable chamber 603 describedabove. It is understood that the following method may be practiced usingany of the inflatable chambers 303, 403, 503, 603, 703.

Referring to FIGS. 17A and 17B, an incision 801 is made at or near theumbilicus and a tunnel 803 is formed from the incision toward the siteof the hernia. The peritoneum P is then dissected from the underlyinglayer U. The tissue layers are preferably dissected with the apparatusand methods described above; however, dissection may also beaccomplished in a conventional manner. For example, dissection may beaccomplished with an endoscope, graspers, an operating scope or anyblunt instrument which may be used to dissect the tissue layers bysweeping the area between the layers.

Once the tissue layers have been dissected, the retraction device isinserted through the tunnel 803 while in the compact deflated conditionof FIG. 11A. When the inflatable chamber 603 is within the working spaceWS, an inflation fluid (any suitable gas or liquid, such as air orsaline) is injected into the inflatable chamber 603 thereby expandingthe inflatable chamber to the shape of FIG. 17A. A conventional handbulb or syringe can be used to inject the fluid through port 353. Theanchor flange 655 is moved toward the distal end and locked in positionso that a compressive force is exerted on the abdominal wall by theanchor flange 655 and inflatable chamber 603. The compressive forceensures that the inflatable chamber 603 forms a seal which inhibits theescape of insufflation gas through the tunnel 803. Insufflation gas isthen passed into the working space WS and the hernia H is then repairedusing the procedure described in connection with FIG. 3I. During repairof the hernia, an additional instrument I may be introduced into theworking chamber in the space 633 between the extensions 629, 631. Thespace 633 permits introduction of the additional instrument I whileminimizing the risk that the additional instrument I might puncture theinflatable chamber 603.

7. Method and Apparatus for Packing Deflated Balloons

As mentioned above, a known method of packing inflatable balloons is toroll the balloon inward from opposing sides of the chamber as shown inFIG. 18. A problem which occurs during inflation of the balloon packedin the known manner of FIG. 18 is that unrolling of the balloon cancause trauma to the tissue layer due to differential motion between thetissue layer and the balloon. Referring to FIG. 19, a balloon 807compacted in the known manner of FIG. 18 is in a partially inflatedstate. During inflation, rolls 809 displaces outwardly with a top edge811 rubbing against the upper tissue layer 813 which can cause trauma tothe tissue layer.

The problem of traumatizing the tissue layers is particularlyproblematic when using an inflatable balloon in the properitoneal space.If the peritoneum is punctured or otherwise breached due to a tearcaused by unrolling of the balloon, the properitoneal space cannotretain pressurized fluid to maintain the space. If pressure is lost, thevolume of the space will decrease and compromise the surgery.

Referring to FIGS. 20 and 21, a preferred balloon 901 for dissecting thepreperitoneal space is shown. The balloon 901 has a kidney-beancross-sectional shape as shown in FIG. 21. It is understood that thepresent invention may be practiced using any shape balloon and theballoon 901 is merely an example. For example, the balloon 901 may alsobe spherical, oblong, cylindrical or any other shape suited for theparticular dissection and/or retraction contemplated.

The balloon 901 is preferably mounted to an inflation and deliverydevice as shown in FIG. 2A but may also be attached to any otherinflation and delivery device. The balloon is mounted to an introducertube 903 having a bore 904 with a circular cross-section that canaccommodate an endoscope. The bore 904 houses a fluid path 906 forinflating the balloon. The proximal end of the introducer tube is fittedwith a port 905 in which is mounted a flapper valve 907. The shutter ofthe flapper valve is operated by a button 909. The flapper valve forms agas-tight seal with an endoscope or other instrument inserted though theflapper valve into the bore of the introducer tube. The port is alsofitted with a valve 911 to which a supply of a suitable inflation fluidcan be connected. The inflation fluid passes through the valve,introducer tube and into the balloon 901.

The balloon 901 is preferably formed from first and second sheets 913,915 in the manner described above in connection with the inflatablechambers of FIGS. 11-16. The balloon 901 is also preferably made of thematerials and fabricated in the manner described above in connectionwith FIGS. 11-16. Other preferred materials include latex, siliconerubber, or polyurethane. Furthermore, although the term balloon is used,the inflatable balloon may be elastic or inelastic.

Referring to FIG. 22, a first portion 917 of the balloon isdisplaced-inwardly toward the interior of the balloon in accordance witha preferred method of packing the balloon. Although it is preferred todisplace the first portion 917 of the balloon in a directionperpendicular to a longitudinal axis 919 of the introducer tube 903, theballoon 901 may also be displaced inwardly in any other direction.

The first inwardly-displaced portion is then preferably rolled-up withinthe interior of the balloon with a rolling device 921 inserted throughthe bore of the introducer tube 903. Referring to FIGS. 23 and 24, therolling device 921 includes two rolling rods 923 for grasping the firstinwardly-displaced portion 917. Each rod 923 has a diameter of about ⅛inch and a gap of preferably less than {fraction (1/16)} inchtherebetween. The gap size and diameter of the rods 923 may vary, ofcourse, depending on the thickness of the balloon material. Furthermore,the rolling device 921 may include any other feature for grasping theinwardly displaced portion, such as a pair of jaws, a clamp or a pair ofelastically deformable arms. The rolling device has a knurled handle formanipulating the rolling device.

The rolling device 921 is rotated to roll the first portion as shown inFIG. 25. After the first portion has been rolled into a sufficientlycompact roll, a second portion of the balloon is displaced inwardly androlled in the same manner. The two rolls 929, 931 are then housed withina sheath 933 as described above in conjunction with the inflatablechambers of FIGS. 11-16. An obturator 935 is positioned in the bore ofthe introducer tube and between the two rolls 929, 931 to providestructural support for the balloon 901 during insertion into thepatient. The obturator 935 is also shown in FIGS. 2E, 11A and 11B. Therolls 929, 931 are positioned on opposite sides of the obturator 935with the obturator 935 including concave portions 937 for receiving therolls 929, 931.

The compact, deflated balloon is introduced into the patient between thetwo tissue layers to be separated and is then inflated. The balloon 901may be used for dissecting and/or retracting tissue planes throughoutthe body. Referring to FIG. 27 which shows the balloon during inflationin the peritoneum, the inwardly-displaced portions evert duringinflation so that differential motion between the balloon 901 andadjacent tissue layers 937 is minimized thereby reducing trauma to thetissue layers.

Although it is preferred to roll the first and second inwardly-displacedportions into first and second rolls 929, 931 within the interior of theballoon 901, the balloon 901 may be packed in any other manner so longas an inwardly-displaced portion is provided which everts duringinflation. Referring to FIGS. 28 and 29, the inwardly-displaced portions917, 927 may also be displaced to a side opposite the initialdisplacement and then rolled-up into the rolls as previously described.This packaging method essentially captures the inverted portions of theballoon such that the inverted portions will completely unroll beforebeginning to evert during inflation.

The first and second inwardly-displaced portions 917, 927 may also berolled in the conventional manner from opposing lateral sides afterdisplacing the portions inward as shown in FIGS. 30 and 31. The firstand second portions 917, 927 divide the balloon 901 into an upper part939 and a lower part 941. The upper part 939, first portion 917 andlower part 941 are then rolled-up in the conventional manner as shown inFIG. 31. When the balloon 901 is rolled in the manner shown in FIG. 30and 31, the balloon 901 will suffer the problem of relatively highdifferential motion between the balloon 901 and the adjacent tissuelayer during the initial inflation and deployment, however, during theend of the inflation, the balloon will have relatively low differentialmotion relative to the tissue layers. This method of packing a balloonis useful when problematic internal structures are positioned laterallyoutward from the obturator.

When the balloon is formed from first and second sheets 913, 915, theupper and lower parts are preferably formed by the first and secondsheets 943, respectively. By configuring the balloon 901 in this manner,the first and second portions include a part of the seam 943 between thefirst and second sheets 913, 915. When coupling the first and secondsheets 913, 915 together with an RF weld, the seam 943 forms arelatively thin, rigid periphery which can cut or otherwise traumatizethe tissue layers. Referring to FIG. 27, the seam 943 everts into aspace 945 between the tissue layers along the lateral edges of theballoon 901 thereby minimizing contact between the seam 943 and thetissue layers.

The balloon 901 may also include a number of inwardly-displaced portionsin the form of accordion-folds 947 as shown in FIG. 32. FIG. 33illustrates the balloon of FIG. 32 in the compact, deflated state.

Although individual preferred embodiments have been described, theinvention may be practiced using any combination of preferred features.For example, a small roll may be formed in the manner shown in the FIGS.23 and 25 followed by the procedure shown in FIG. 31. Furthermore,modification and variation can be made to the disclosed embodimentswithout departing from the subject of the invention as defined by thefollowing claims.

We claim:
 1. A method of separating tissue layers, comprising the stepsof: (a) providing an inflatable balloon having an interior surface whichdefines an opening for receiving fluid for inflating the balloon, saidballoon having a deflated state and an inflated state; (b) when theballoon is in the deflated state with the interior surface substantiallysurrounding a first volume, displacing a first portion of the ballooninwardly; (c) after step (b) but before inflating the balloon, insertingthe balloon into a patient; (d) after step (c), inflating the balloon toseparate adjacent tissue layers in the patient, the first portion of theballoon being everted during inflation of the balloon; (e) after step(b), but before step (c), inserting a rolling device into the firstvolume; (f) after step (e), but before step (c), grasping the firstportion of the balloon with the rolling device; and (g) after step (f),but before step (c), rotating the rolling device so that the firstportion of the balloon is rolled into a first roll.
 2. The method ofclaim 1, further comprising the steps of: (h) after step (g), but beforestep (c), displacing a second portion of the balloon inwardly; (i) afterstep (h), but before step (c), grasping the second portion of theballoon with the rolling device; and (j) after step (i), but before step(c), rotating the rolling device so that the second portion of theballoon is rolled into a second roll.
 3. The method of claim 2, whereinstep (a) includes the steps of providing a support structure having afluid path, the inflatable balloon being attached to the supportstructure with at least a portion of the support structure extendingthrough the opening such that, when said inflatable balloon is in thedeflated state, the first volume is fluidly coupled to the fluid path,and wherein the support structure includes a hollow tube having alongitudinal axis, and wherein steps (b) and (h) are carried out bydisplacing the first and second portions inwardly toward thelongitudinal axis.
 4. A method of separating tissue layers, comprisingthe steps of: (a) providing an inflatable balloon having an interiorsurface which defines an opening for receiving fluid for inflating theballoon, said balloon having a deflated state and an inflated state; (b)when the balloon is in the deflated state with the interior surfacesubstantially surrounding a first volume, displacing a first portion ofthe balloon inwardly forming a folded portion separating the ballooninto an upper part, a lower part and a fold therebetween; (c) after step(b) but before inflating the balloon, inserting the balloon into apatient; and (d) after step (c), inflating the balloon to separateadjacent tissue layers in the patient, the first portion of the balloonbeing everted during inflation of the balloon, and (e) after step (b)but before step (c), rolling the upper part, the lower part, and thefold together to form a roll.
 5. The method of claim 4, wherein step (a)comprises the step of: coupling together a first sheet and a secondsheet to form the balloon, the first sheet including the upper part andthe second sheet including the lower part.
 6. A method of separatingtissue layers, comprising the steps of: (a) providing an inflatableballoon having an interior surface which defines an opening forreceiving fluid for inflating the balloon, said balloon having adeflated state and an inflated state; (b) when the balloon is in thedeflated state with the interior surface substantially surrounding afirst volume, displacing a first portion of the balloon inwardly forminga folded portion separating the balloon into an upper part, a lower partand a fold therebetween; (c) after step (b) but before inflating theballoon, inserting the balloon into a patient; and (d) after step (c),inflating the balloon to separate adjacent tissue layers in the patient,the upper part contacting one of the tissue layers and the lower partcontacting an other of the tissue layers, and the first portion beingpositioned between the upper and lower parts and being everted duringinflation of the balloon.
 7. A method of separating tissue layers,comprising the steps of: (a) providing an inflatable balloon having aninterior surface which defines an opening for receiving fluid forinflating the balloon, said balloon also having a deflated state and aninflated state, and an exterior surface; (b) when the balloon is in thedeflated state, inverting a part of the balloon inwardly to form afolded portion which separates the balloon into an upper part, a lowerpart, and a fold therebetween, and rolling the folded portion to form afirst portion; (c) after step (b), inserting the balloon into a patient;and (d) after step (c), inflating the balloon to separate adjacenttissue layers in the patient, the first portion of the balloon beingeverted and unrolled during inflation of the balloon.
 8. The method ofclaim 7, wherein step (b) also includes the step of: when the balloon isin the deflated state, inverting another part of the balloon inwardly toform a second folded portion of the balloon, and rolling the secondfolded portion to form a second portion of the balloon, and whereinduring step (d), the second portion of the balloon is everted andunrolled.
 9. The method of claim 7, also including the steps of: (e)after step (b) but before step (c), covering the balloon with a sheathwhen the balloon is in the deflated states.
 10. A method of packingdevice for separating tissue layers, comprising the steps of: (a)providing an inflatable balloon having a deflated state, an inflatedstate, an exterior surface, an interior surface, and an interior; (b)when the balloon is in the deflated state, inverting a part of theballoon inwardly to form a folded portion which separates the ballooninto an upper part, a lower part, and a fold therebetween, and rollingthe folded portion to form a first portion; and (c) when the balloon isin the deflated state, inverting another part of the balloon inwardly toform a second folded portion of the balloon, and rolling the secondfolded portion to form a second portion.
 11. The method of claim 10,also including the step of: (d) after steps (b) and (c), covering theballoon with a sheath when the balloon is in the deflated state.
 12. Themethod of claim 10, followed by (also including) the steps of: (d) aftersteps (b) and (c), inserting the balloon into a patient; and (e) afterstep (d) inflating the balloon to separate adjacent tissue layers in thepatient, the first portion of′ the balloon being everted and unrolledduring inflation of the balloon, and the second portion of the balloonalso being everted and unrolled during said inflation of the balloon.